(btw i work at an audio shop, so this is advice) okay, to start off you have 4x6's in the front and 4x10's in the back, so depending on if you want a sub or not would depend on what ud want to do, if you do want a sub, just instead of putting 4x6's and 4x10's back in, just do 4" coaxal speakers, probably lightning audio or orion or kenwood would work best for you, just dont get any high series ones that would need to be amped, if you dont want a sub, just put like kenwood 4x6's and 4x10 back in it, and also, be careful if you try to mix and match speakers, cuz it usually doesnt turn out too well

I am wanting to jump this thread back into life! I recently purchased a 94 fullsize Blazer like the OP of this thread. I see the front speakers that are in the dash. However, I do not have sound anywhere in the back and am wondering if there are even speakers in the back! I do not see any slots in the plastic along the sides of the interior. I was hoping someone could show me a picture of where there the back speakers might be hiding or if it is just the two front speakers! I want to replace the set all at once if there are 4 speakers!